UPDATED: Should FDA usher old-style opioid generics onto the market?

On one side stand Endo Health Solutions ($ENDP) and Purdue Pharma. On the other, generic drugmakers that want to introduce copies of big-selling, high-powered painkillers. In the middle, the FDA, which has to decide whether to allow those cheap copies onto the market.

The powerful drugs in question include the notorious "hillbilly heroin," OxyContin, and Endo's competing painkiller, Opana. Under pressure amid a nationwide epidemic of painkiller abuse, both Purdue and Endo pulled their original versions of the drugs and rolled out abuse-resistant formulations. The newer pills are harder to crush for snorting and injecting.

But the generics makers--including Watson Pharmaceuticals ($WPI) and Impax Laboratories ($IPXL)--want to market copies of the older formulations, without crush-resistant protections. Unfair, say Endo and Purdue, which admittedly spent big money developing and testing their new formulas. And Endo has sued the FDA to protect that investment, seeking to block generic versions. Meanwhile, the FDA itself has been encouraging drugmakers to develop tamper-resistant pain pills.

Now, at least one study has found that tamper-resistant versions of these drugs appear to be putting a damper on abuse. But it was funded by Endo--and the company added the data to its citizen petition against generic Opana.

The Generic Pharmaceutical Association has a point in saying that Endo and Purdue waited to launch tamper-resistant pills until patents on the originals neared expiration. "There is obviously a dollar motive to this and, if we can't touch the technology, then generics are kept out of the marketplace completely," GPhA's Brynna Clark told the Financial Times.

But Purdue Pharma started working on an tamper-resistant OxyContin formula more than a decade ago, the company says, in response to reports of abuse and diversion. "[D]rug development and regulatory review of a medication is a difficult process and it can often take several years to complete," spokesman Jim Heins points out. "If we could have brought a reformulation to the market sooner, we would have done so."

The abuse-deterrent formulas may get legislative support. In July, a group of congressional representatives sponsored a bill requiring strong painkillers to use tamper-resistant technology. Obviously, legislation would render the tug-of-war moot. But unless and until that happens, the FDA has a philosophical wrangle on its hands. A decision isn't likely this year, the agency has said.